**Core Concept**
Drug-induced lupus erythematosus (DILE) is a rare autoimmune disorder triggered by certain medications, characterized by the production of autoantibodies and a clinical presentation similar to systemic lupus erythematosus (SLE). The pathogenesis of DILE involves the formation of immune complexes and the activation of various immune cells.

**Why the Correct Answer is Right**
The correct answer is **Anti-histone antibodies**. These antibodies are highly specific for DILE and can be detected in up to 80% of patients. The presence of anti-histone antibodies is thought to be a marker of the autoimmune response triggered by the offending medication. In contrast to SLE, where anti-histone antibodies are less common, the presence of these antibodies in a patient with a medication history suggests DILE.

**Why Each Wrong Option is Incorrect**
**Option A:** Anti-ribonucleoprotein (RNP) antibodies are more commonly associated with mixed connective tissue disease and are not specific for DILE.
**Option B:** Anti-Smith (Sm) antibodies are highly specific for SLE and are not typically seen in DILE.
**Option C:** Anti-double-stranded DNA (dsDNA) antibodies are also highly specific for SLE and are not a marker for DILE.

**Clinical Pearl / High-Yield Fact**
The most common medications associated with DILE include hydralazine, procainamide, and isoniazid. It is essential to consider DILE in patients taking these medications who present with symptoms suggestive of SLE.

**Correct Answer:** D. Anti-histone antibodies